2.0 Analysis 2.1 Introduction Because no evidence could be found to indicate that the aircraft was not airworthy prior to impact, it was necessary to concentrate on the human and environmental issues in order to determine why the accident occurred. The following analysis, therefore, concentrates on the probable approach profile for Empress 204 leading to the accident site, the possibility of airframe icing, crew coordination, the unserviceable radio altimeter, flap and gear position, and controlled flight into terrain. 2.2 Descent Profile Recorded Moncton ACC radar data shows that the aircraft, after being cleared for the approach at Bathurst, stopped the descent at 6,000 feet and maintained this altitude until it disappeared from radar 11 miles back from the Bathurst beacon. The aircraft was maintaining a ground speed of approximately 200 knots and the captain may have wanted to take advantage of the tail wind at this altitude as long as possible. Another possibility is that the captain may have wanted to stay above the cloud tops at 6,000 feet asl to avoid flight in the area of turbulence and/or airframe icing as long as he could. Either of these two possibilities sets up a situation where a high rate of descent, approximately 1,500 feet per minute (fpm), would be required to successfully carry out the NDB/DME approach to runway 10. The high rate of descent would minimize the amount of time the aircraft would be in cloud. In order to keep airspeed and engine operating temperatures within acceptable limits during the descent, the crew likely extended the flaps to 15 degrees and lowered the gear. 2.3 Airframe Icing Pilot reports from other aircraft crews reported only traces of airframe icing in the vicinity of Bathurst during that period. The crew of Empress 204 did not indicate they were unable to maintain safe flight due to airframe icing, and there was no indication of airframe icing at the accident site. The aircraft was 1,354 lb under maximum all-up weight at the time of the occurrence. At this weight and with operational de-icing equipment, which was functionally checked serviceable prior to departure, the aircraft would not have had any problems maintaining controlled flight in the icing conditions that existed at the time. Because of these factors, it is unlikely that airframe icing was a contributing factor in this accident. 2.4 Controlled Flight Into Terrain The absence of any pre-impact aircraft deficiencies, the absence of any emergency call from the crew, and the aircraft attitude when it struck the trees indicate that this was a controlled flight into terrain accident. There are two possibilities, neither of which can be established, as to why the aircraft descended to such a low altitude. One possible explanation for the low altitude is that the crew unintentionally descended below the minimum descent altitude for the approach. Increased caution would have been required with controlling and configuring the aircraft during the high rate of descent required during this approach, particularly since the crew may have been preoccupied with checking for airframe icing. The co-pilot was responsible for altitude callouts. The altimeter would have been decreasing quite rapidly at 1,500 fpm. Instrumentation lighting may have been turned to a minimum to help the crew visually acquire the runway environment, especially considering the weather and lighting conditions that existed at the time. This might explain why the crew did not stop their descent at the MDA for the approach. The other possibility is that the crew intentionally descended below minimums to visually acquire the ground. The MDA ensures adequate terrain clearance for an aircraft inside the approach beacon until the crew can visually acquire the runway environment. The aircraft crashed 3.75 nm from the airport at an elevation 250 feet below the MDA. Considering the weather and light conditions that existed at the time, it is highly unlikely that the crew could have seen the runway this far back from the airport. 2.5 Unserviceable Radio Altimeter Had the radio altimeter been serviceable and set correctly during the approach for the MDA, it is possible that this instrument might have alerted the crew in sufficient time for them to have recovered from their low altitude. 2.6 Flap and Gear Position The position of the flaps and right main gear D door indicates the possibility that the crew may have recognized their situation and started an overshoot just moments prior to the impact. The procedure for executing an overshoot or missed approach in this aircraft is to advance the power to full, retract the flaps and landing gear, and pitch the nose up to a climb attitude. The flaps would not normally be selected for the seven-degree deflection position that they were found in after the accident. This indicates that they were travelling either up or down at the time of impact. As the flaps would normally be selected to fifteen degrees or more, well before this point on the approach, it is more likely they were travelling up. The position of the right main gear D door at impact suggests that either the gear extension cycle was just ending or the retraction cycle was just beginning. As it is likely that the captain set the aircraft up in a steep descent, it is probable that the gear had been extended early in the descent from 6,000 feet to create additional drag which would help keep the speed under control and allow the crew to maintain enough engine power to help keep engine operating temperatures at an acceptable level. Because of this probability, the landing gear was more likely beginning the retraction cycle at impact. 2.7 Survival Aspects The 3 hours it took to locate the aircraft was influenced by the following factors: the aircraft was not equipped with an ELT, the Bathurst personnel assumed that the aircraft had overshot and that the crew had not informed them, and the weather at the airport was poor. Although the Bathurst Airport has an AEP manual, it is not apparent that this aided the individuals involved in assessing or responding to this accident. 3.0 Conclusions 3.1 Findings The aircraft crashed on the approach to runway 10, 3 miles from the runway threshold during darkness. The pilot and co-pilot sustained fatal injuries at impact. The captain's medical was invalid at the time the accident occurred. The aircraft's emergency locator transmitter had been removed for recertification and was not re-installed in the aircraft, nor was it required by regulations. The aircraft was equipped with a radio altimeter, which was unserviceable during the ten months prior to the accident; this equipment was not required by regulations. The aircraft's weight and centre of gravity were within limits. The aircraft was complete, intact, and functioning normally before it struck trees. Based on the autopsy, toxicology, and medical records, there was no evidence to indicate that the crew's performance was degraded by physiological factors. It took three hours and forty-five minutes to locate the downed aircraft. The crew of Empress 204 did not monitor their descent and the aircraft descended below the minimum descent altitude for the approach. 3.2 Causes The crew of Empress 204 allowed the aircraft to descend below the minimum descent altitude for the approach. The Board has no aviation safety recommendations to issue at this time.4.0 Safety Action The Board has no aviation safety recommendations to issue at this time.